BTJCCINUM. 365 



Fig. 18. Odontoplioral cartilage (odoutophoral tongue) 



with ventral muscles indicated through it. 



Slightly magnified. 

 Fig. 19. Odontoj)hore from above before muscles are 



laid bare by cutting dorsal transverse 



sheath. Slightly magnified. 

 Fig. 20. Odoutophoral tongue. 

 Fig. 21. Anterior end of odoutophoral cartilage with 



ventral protractor muscles. 

 Fig. 22. Transverse section of cartilage and radula 



muscles. x 480. 

 Fig. 23. Transverse section near tip of odoutophoral 



tongue. 

 Fig. 24. Transverse section of pharynx wall. x 200. 

 Fig. 25. Transverse section of oesophagus. x 30. 



Plate IY. 



Fig. 26. Section through salivary gland and duct. 



x 450. 

 Fig. 27. Epithelium of oesophagus. x 800. 

 Fig. 28. Transverse section of oesophageal caecum. 



X 50. 

 Fig. 29. Transverse section of digestive gland. 



X 200. 

 Fig. 30. Section through wall of Gland of Leiblein. 



X 450. 

 Fig. 31. Transverse section tlirough two gill leaflets. 

 Fig. 32. Transverse section through gill leaflet more 



distal to fig. 31. 

 Fig. 33. Transverse section through gill leaflet more 

 distal to fig. 32. 

 (The three sections are consecutive and all x 100.) 

 Fig. 34. Cells from inner surface of wall of gill, x 800. 



